Abstract

The forkhead domain or box represents an evolutionarily conserved DNA‐binding motif of winged helix structure that has a degree
of similarity to the helix–turn–helix motif found in other DNA‐binding proteins. Forkhead box (Fox) proteins are involved
in a variety of biological processes such as early embryogenesis, organogenesis, tumorigenesis and signal transduction.

Structure and scheme of the forkhead/winged helix domain of HNF‐3γ (FoxA3). Structural data are from Clark et al., . Note that the forkhead domain comprises three α‐helices (H1, H2 and H3), three β‐strands (S1, S2 and S3), two wings (W1
and W2) and a turn‐like structure (T′). Main deoxyribonucleic acid (DNA) contacts are formed by H3, located within the major groove. C: carboxy‐terminus; N: amino‐terminus.